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Reassessing the Age Limit of Precocious Puberty in Girls

Am Fam Physician. 2000 Mar 15;61(6):1850-1852.

Standard textbooks usually define precocious puberty as “development of secondary sexual characteristics” in girls less than eight years of age. However, puberty seems to be occurring earlier now than in the past. Kaplowitz and colleagues reviewed existing data and issued some guidelines for evaluation and treatment of girls with possible precocious puberty.

Breast tissue development is the most accurate physical sign of puberty (activation of the pituitary-gonadal axis) in girls. Pubic hair usually appears at about the same time breast tissue development begins. Age estimates of onset of puberty are usually based on a 1969 study in which it was found that Tanner stage 2 breast development and stage 2 pubic hair development occurred at 11.15 ± 1.1 years and at 11.69 ± 1.21 years, respectively. Current studies, however, seem to indicate that these stages are now reached earlier (approximately one year earlier in white girls and two years earlier in black girls). Therefore, the youngest ages at which development will occur (and below which evaluation is needed) are lower than the new means.

Based on evaluation of available studies, the following recommendations have been made about when an evaluation is needed. First, a white girl who has breast or pubic hair development before age seven or a black girl who has this development before age six should be referred for further evaluation. Premature adrenarche (a normal variant) will be the most likely diagnosis in girls who present with pubic hair development but no breast development before age eight. Girls who exhibit evidence of other androgen production (e.g., rapid growth, clitoral enlargement or early onset of acne) will need to be evaluated for other virilizing disorders.

The second recommendation for further evaluation concerns patients with breast development beginning after age seven in white girls or age six in black girls who also have the following additional conditions: (1) a bone age more than two years ahead of their chronologic age and a predicted height that is at least two standard deviations below their genetic predicted height (for girls: the father's height [in inches] + the mother's height −5 inches ÷ 2); (2) a new onset of headaches, seizures or focal neurologic findings or a pre-existing neurologic problem; or (3) behaviors suggesting that puberty progression is adversely affecting emotional development. Obtaining a bone age determination would be appropriate in girls who are not above the 50th percentile in height or in whom breast development and puberty seem to be accelerated. This determination could help guide a decision about the use of gonadotropin-releasing hormone (GnRH) agonist therapy. If the girl's status is unclear, a re-examination in three to six months is reasonable. No good evidence exists to prove that the use of GnRH agonists in girls meeting these criteria (nonaccelerated puberty and an acceptable predicted adult height) improves adult height.

The committee made no changes to lower the age-limit recommendations about evaluation of boys with precocious puberty because a significant trend toward earlier maturation in males has not been evident.

Kaplowitz PB,
et al.
Reexamination of the age limit for defining when puberty is precocious in girls in the United States: implications for evaluation and treatment. Pediatrics.
October 1999;104:936–41.